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Wang Y, Lilienfeldt N, Hekimi S. Understanding coenzyme Q. Physiol Rev 2024; 104:1533-1610. [PMID: 38722242 DOI: 10.1152/physrev.00040.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 04/08/2024] [Accepted: 05/01/2024] [Indexed: 08/11/2024] Open
Abstract
Coenzyme Q (CoQ), also known as ubiquinone, comprises a benzoquinone head group and a long isoprenoid side chain. It is thus extremely hydrophobic and resides in membranes. It is best known for its complex function as an electron transporter in the mitochondrial electron transport chain (ETC) but is also required for several other crucial cellular processes. In fact, CoQ appears to be central to the entire redox balance of the cell. Remarkably, its structure and therefore its properties have not changed from bacteria to vertebrates. In metazoans, it is synthesized in all cells and is found in most, and maybe all, biological membranes. CoQ is also known as a nutritional supplement, mostly because of its involvement with antioxidant defenses. However, whether there is any health benefit from oral consumption of CoQ is not well established. Here we review the function of CoQ as a redox-active molecule in the ETC and other enzymatic systems, its role as a prooxidant in reactive oxygen species generation, and its separate involvement in antioxidant mechanisms. We also review CoQ biosynthesis, which is particularly complex because of its extreme hydrophobicity, as well as the biological consequences of primary and secondary CoQ deficiency, including in human patients. Primary CoQ deficiency is a rare inborn condition due to mutation in CoQ biosynthetic genes. Secondary CoQ deficiency is much more common, as it accompanies a variety of pathological conditions, including mitochondrial disorders as well as aging. In this context, we discuss the importance, but also the great difficulty, of alleviating CoQ deficiency by CoQ supplementation.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Noah Lilienfeldt
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Quebec, Canada
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2
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Nesci S, Rubattu S. UCP2, a Member of the Mitochondrial Uncoupling Proteins: An Overview from Physiological to Pathological Roles. Biomedicines 2024; 12:1307. [PMID: 38927514 PMCID: PMC11201685 DOI: 10.3390/biomedicines12061307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2024] [Revised: 06/07/2024] [Accepted: 06/10/2024] [Indexed: 06/28/2024] Open
Abstract
UCP2 is an uncoupling protein homolog to UCP1. Unlike UCP1, which participates in non-shivering thermogenesis by uncoupling oxidative phosphorylation (OXPHOS), UCP2 does not perform a canonical H+ leak, consuming the protonmotive force (Δp) through the inner mitochondrial membrane. The UCP2 biological role is elusive. It can counteract oxidative stress, acting with a "mild uncoupling" process to reduce ROS production, and, in fact, UCP2 activities are related to inflammatory processes, triggering pathological conditions. However, the Δp dissipation by UCP2 activity reduces the mitochondrial ATP production and rewires the bioenergetic metabolism of the cells. In all likelihood, UCP2 works as a carrier of metabolites with four carbon atoms (C4), reversing the anaerobic glycolysis-dependent catabolism to OXPHOS. Indeed, UCP2 can perform catalysis in dual mode: mild uncoupling of OXPHOS and metabolite C4 exchange of mitochondria. In vivo, the UCP2 features in the biology of mitochondria promote healthy ageing, increased lifespan, and can assure cerebro- and cardiovascular protection. However, the pathological conditions responsible for insulin secretion suppression are dependent on UCP2 activity. On balance, the uncertain biochemical mechanisms dependent on UCP2 do not allow us to depict the protective role in mitochondrial bioenergetics.
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Affiliation(s)
- Salvatore Nesci
- Department of Veterinary Medical Sciences, Alma Mater Studiorum University of Bologna, 40064 Ozzano Emilia, Italy;
| | - Speranza Rubattu
- Department of Clinical and Molecular Medicine, School of Medicine and Psychology, “Sapienza” University of Rome, 00189 Rome, Italy
- IRCCS Neuromed, 86077 Pozzilli, Italy
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3
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Caggiano EG, Taniguchi CM. UCP2 and pancreatic cancer: conscious uncoupling for therapeutic effect. Cancer Metastasis Rev 2024; 43:777-794. [PMID: 38194152 PMCID: PMC11156755 DOI: 10.1007/s10555-023-10157-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 11/13/2023] [Indexed: 01/10/2024]
Abstract
Pancreatic cancer has an exaggerated dependence on mitochondrial metabolism, but methods to specifically target the mitochondria without off target effects in normal tissues that rely on these organelles is a significant challenge. The mitochondrial uncoupling protein 2 (UCP2) has potential as a cancer-specific drug target, and thus, we will review the known biology of UCP2 and discuss its potential role in the pathobiology and future therapy of pancreatic cancer.
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Affiliation(s)
- Emily G Caggiano
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
| | - Cullen M Taniguchi
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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4
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Arabzadeh E, Shirvani H, Masjedi MR, Ghanei M, Hofmeister M, Rostamkhani F. Treadmill exercise with nanoselenium supplementation affects the expression of Irisin/FNDC5 and semaphorin 3A in rats exposed to cigarette smoke extract. 3 Biotech 2024; 14:4. [PMID: 38058362 PMCID: PMC10695908 DOI: 10.1007/s13205-023-03849-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 11/08/2023] [Indexed: 12/08/2023] Open
Abstract
In the current study, we investigated the impacts of 6 weeks of aerobic interval training (AIT) with selenium nanoparticles (SeNPs) on muscle, serum, and lung irisin (FNDC5) and Sema3A in rats exposed to cigarette smoke extract (CSE). To this end, 49 male Wistar rats (8 weeks old) were divided into seven groups: control, SeNPs (2.5 mg/kg b.w by oral gavage, 3 days/week, 6 weeks), AIT (49 min/day, 5 days/week for 6 weeks, interval), SeNPs + AIT, CSE (150 µL by IP injection, 1 day/week for 6 weeks), CSE + AIT, and CSE + SeNPs + AIT. The CSE group showed a significant reduction in irisin and Sema3A serum levels, as well as a decrease in FNDC5 and Sema3A gene expression in lung tissue (p < 0.05). A combined treatment (AIT with SeNPs) significantly increased the serum level and the expression of muscle and lung irisin (FNDC5) and Sema3A in CSE received groups (p < 0.05). There was a positive and significant correlation between muscle FNDC5 and lung FNDC5 in the CSE + SeNPs + AIT group (r = 0.92, p = 0.025). In addition, there was a positive and significant correlation between serum Sema3A and lung Sema3A of CSE + SeNPs + AIT group (r = 0.97, p = 0.004). Seemingly, performing aerobic exercises with the antioxidant and anti-inflammatory supplement nano-selenium in the model of lung damage (similar to COPD) can boost myokine irisin and Sema3A, especially in serum and lung tissue. These results displayed the paracrine/endocrine regulatory function of these myokines on other tissues. In other words, these interventions emphasized the creation of crosstalk between skeletal muscles and damaged lung, focusing on its recovery; however, further research is needed.
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Affiliation(s)
- Ehsan Arabzadeh
- Exercise Physiology Research Center, Life Style Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Hossein Shirvani
- Exercise Physiology Research Center, Life Style Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Masjedi
- Tobacco Control Research Center (TCRC), Iranian Anti-Tobacco Association, Tehran, Iran
| | - Mostafa Ghanei
- Chemical Injuries Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Martin Hofmeister
- Department of Food and Nutrition, Consumer Centre of the German Federal State of Bavaria, Munich, Germany
| | - Fatemeh Rostamkhani
- Department of Biology, Yadegar-e-Imam Khomeini (RAH) Shahre Rey Branch, Islamic Azad University, Tehran, Iran
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5
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Segalés J, Sánchez-Martín C, Pujol-Morcillo A, Martín-Ruiz M, de Los Santos P, Lobato-Alonso D, Oliver E, Rial E. Role of UCP2 in the Energy Metabolism of the Cancer Cell Line A549. Int J Mol Sci 2023; 24:ijms24098123. [PMID: 37175829 PMCID: PMC10179244 DOI: 10.3390/ijms24098123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/21/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
The uncoupling protein UCP2 is a mitochondrial carrier for which transport activity remains controversial. The physiological contexts in which UCP2 is expressed have led to the assumption that, like UCP1, it uncouples oxidative phosphorylation and thereby reduces the generation of reactive oxygen species. Other reports have involved UCP2 in the Warburg effect, and results showing that UCP2 catalyzes the export of matrix C4 metabolites to facilitate glutamine utilization suggest that the carrier could be involved in the metabolic adaptations required for cell proliferation. We have examined the role of UCP2 in the energy metabolism of the lung adenocarcinoma cell line A549 and show that UCP2 silencing decreased the basal rate of respiration, although this inhibition was not compensated by an increase in glycolysis. Silencing did not lead to either changes in proton leakage, as determined by the rate of respiration in the absence of ATP synthesis, or changes in the rate of formation of reactive oxygen species. The decrease in energy metabolism did not alter the cellular energy charge. The decreased cell proliferation observed in UCP2-silenced cells would explain the reduced cellular ATP demand. We conclude that UCP2 does not operate as an uncoupling protein, whereas our results are consistent with its activity as a C4-metabolite carrier involved in the metabolic adaptations of proliferating cells.
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Affiliation(s)
- Jessica Segalés
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Carlos Sánchez-Martín
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Aleida Pujol-Morcillo
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Marta Martín-Ruiz
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Patricia de Los Santos
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Daniel Lobato-Alonso
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Eduardo Oliver
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
| | - Eduardo Rial
- Centro de Investigaciones Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
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Zorova LD, Pevzner IB, Khailova LS, Korshunova GA, Kovaleva MA, Kovalev LI, Serebryakova MV, Silachev DN, Sudakov RV, Zorov SD, Rokitskaya TI, Popkov VA, Plotnikov EY, Antonenko YN, Zorov DB. Mitochondrial ATP Synthase and Mild Uncoupling by Butyl Ester of Rhodamine 19, C4R1. Antioxidants (Basel) 2023; 12:antiox12030646. [PMID: 36978894 PMCID: PMC10044837 DOI: 10.3390/antiox12030646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
The homeostasis of the transmembrane potential of hydrogen ions in mitochondria is a prerequisite for the normal mitochondrial functioning. However, in different pathological conditions it is advisable to slightly reduce the membrane potential, while maintaining it at levels sufficient to produce ATP that will ensure the normal functioning of the cell. A number of chemical agents have been found to provide mild uncoupling; however, natural proteins residing in mitochondrial membrane can carry this mission, such as proteins from the UCP family, an adenine nucleotide translocator and a dicarboxylate carrier. In this study, we demonstrated that the butyl ester of rhodamine 19, C4R1, binds to the components of the mitochondrial ATP synthase complex due to electrostatic interaction and has a good uncoupling effect. The more hydrophobic derivative C12R1 binds poorly to mitochondria with less uncoupling activity. Mass spectrometry confirmed that C4R1 binds to the β-subunit of mitochondrial ATP synthase and based on molecular docking, a C4R1 binding model was constructed suggesting the binding site on the interface between the α- and β-subunits, close to the anionic amino acid residues of the β-subunit. The association of the uncoupling effect with binding suggests that the ATP synthase complex can provide induced uncoupling.
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Affiliation(s)
- Ljubava D. Zorova
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
- V.I. Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, 117997 Moscow, Russia
| | - Irina B. Pevzner
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
- V.I. Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, 117997 Moscow, Russia
| | - Ljudmila S. Khailova
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
| | - Galina A. Korshunova
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
| | - Marina A. Kovaleva
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia
| | - Leonid I. Kovalev
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia
| | - Marina V. Serebryakova
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
| | - Denis N. Silachev
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
| | - Roman V. Sudakov
- N.N. Blokhin Russian Cancer Research Center, 115478 Moscow, Russia
| | - Savva D. Zorov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119992 Moscow, Russia
| | - Tatyana I. Rokitskaya
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
| | - Vasily A. Popkov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
- V.I. Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, 117997 Moscow, Russia
| | - Egor Y. Plotnikov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
- V.I. Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, 117997 Moscow, Russia
- Correspondence: (E.Y.P.); (Y.N.A.); (D.B.Z.); Tel.: +7-495-939-5944 (E.Y.P.)
| | - Yuri N. Antonenko
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
- Correspondence: (E.Y.P.); (Y.N.A.); (D.B.Z.); Tel.: +7-495-939-5944 (E.Y.P.)
| | - Dmitry B. Zorov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
- V.I. Kulakov National Medical Research Center of Obstetrics, Gynecology and Perinatology, 117997 Moscow, Russia
- Correspondence: (E.Y.P.); (Y.N.A.); (D.B.Z.); Tel.: +7-495-939-5944 (E.Y.P.)
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7
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Luby A, Alves-Guerra MC. UCP2 as a Cancer Target through Energy Metabolism and Oxidative Stress Control. Int J Mol Sci 2022; 23:ijms232315077. [PMID: 36499405 PMCID: PMC9735768 DOI: 10.3390/ijms232315077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 11/25/2022] [Accepted: 11/27/2022] [Indexed: 12/02/2022] Open
Abstract
Despite numerous therapies, cancer remains one of the leading causes of death worldwide due to the lack of markers for early detection and response to treatment in many patients. Technological advances in tumor screening and renewed interest in energy metabolism have allowed us to identify new cellular players in order to develop personalized treatments. Among the metabolic actors, the mitochondrial transporter uncoupling protein 2 (UCP2), whose expression is increased in many cancers, has been identified as an interesting target in tumor metabolic reprogramming. Over the past decade, a better understanding of its biochemical and physiological functions has established a role for UCP2 in (1) protecting cells from oxidative stress, (2) regulating tumor progression through changes in glycolytic, oxidative and calcium metabolism, and (3) increasing antitumor immunity in the tumor microenvironment to limit cancer development. With these pleiotropic roles, UCP2 can be considered as a potential tumor biomarker that may be interesting to target positively or negatively, depending on the type, metabolic status and stage of tumors, in combination with conventional chemotherapy or immunotherapy to control tumor development and increase response to treatment. This review provides an overview of the latest published science linking mitochondrial UCP2 activity to the tumor context.
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8
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Xia F, Chen H, Jin Z, Fu Z. Apelin-13 protects the lungs from ischemia-reperfusion injury by attenuating inflammatory and oxidative stress. Hum Exp Toxicol 2021; 40:685-694. [PMID: 33025833 DOI: 10.1177/0960327120961436] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Apelin has been reported to regulate mitochondrial function in myocardial ischemia-reperfusion injury and cerebral ischemia-reperfusion injury. However, the role of apelin-13 in lung ischemia-reperfusion injury (LIRI) remains unclear. This study established an experimental rat model to evaluate the underlying mechanisms of apelin-13 on LIRI. Twenty-four rats were randomly divided to sham operation group (group SM), ischemia/reperfusion group (group IR), and apelin-13 treatment group (group APL). The effects of apelin-13 on LIRI were determined histologically using H&E staining, while the wet/dry weight ratio was used to assess lung edema caused by LIRI. Inflammatory cytokines were also detected in Bronchoalveolar lavage (BAL) fluid by ELISA. The protein expression of UCP2 and the morphological changes of mitochondria were determined by western blotting and electromicroscopy, respectively. The results demonstrated the structural damage of lung tissues and lung edema in group IR. An increased level of inflammatory cytokines including IL-1β, IL-6 and TNF-α was observed in rats with LIRI using ELISA. After that, oxidative stress and morphological damage of mitochondria were also shown in group IR. Yet, the application of apelin-13 reversed all these deleterious effects in group APL. The protective effects of apelin-13 were indicated by decreased reactive oxygen species (ROS) and elevated UCP2 expression levels in rats. In conclusion, this study revealed that apelin-13 had protective effects against LIRI via attenuating lung edema, the production of inflammatory cytokines, oxidative stress and mitochondrial dysfunction.
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Affiliation(s)
- F Xia
- Department of Pain Management, Shandong Provincial Hospital, Cheeloo College of Medicine, 12589Shandong University, Jinan, Shandong Province, China
- Department of Anesthesiology, 89657The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - H Chen
- Department of Anesthesiology, 89657The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Z Jin
- Department of Anesthesiology, 89657The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Z Fu
- Department of Pain Management, Shandong Provincial Hospital, Cheeloo College of Medicine, 12589Shandong University, Jinan, Shandong Province, China
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9
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van Dierendonck XAMH, Sancerni T, Alves-Guerra MC, Stienstra R. The role of uncoupling protein 2 in macrophages and its impact on obesity-induced adipose tissue inflammation and insulin resistance. J Biol Chem 2021; 295:17535-17548. [PMID: 33453996 DOI: 10.1074/jbc.ra120.014868] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 10/07/2020] [Indexed: 12/22/2022] Open
Abstract
The development of a chronic, low-grade inflammation originating from adipose tissue in obese subjects is widely recognized to induce insulin resistance, leading to the development of type 2 diabetes. The adipose tissue microenvironment drives specific metabolic reprogramming of adipose tissue macrophages, contributing to the induction of tissue inflammation. Uncoupling protein 2 (UCP2), a mitochondrial anion carrier, is thought to separately modulate inflammatory and metabolic processes in macrophages and is up-regulated in macrophages in the context of obesity and diabetes. Here, we investigate the role of UCP2 in macrophage activation in the context of obesity-induced adipose tissue inflammation and insulin resistance. Using a myeloid-specific knockout of UCP2 (Ucp2ΔLysM), we found that UCP2 deficiency significantly increases glycolysis and oxidative respiration, both unstimulated and after inflammatory conditions. Strikingly, fatty acid loading abolished the metabolic differences between Ucp2ΔLysM macrophages and their floxed controls. Furthermore, Ucp2ΔLysM macrophages show attenuated pro-inflammatory responses toward Toll-like receptor-2 and -4 stimulation. To test the relevance of macrophage-specific Ucp2 deletion in vivo, Ucp2ΔLysM and Ucp2fl/fl mice were rendered obese and insulin resistant through high-fat feeding. Although no differences in adipose tissue inflammation or insulin resistance was found between the two genotypes, adipose tissue macrophages isolated from diet-induced obese Ucp2ΔLysM mice showed decreased TNFα secretion after ex vivo lipopolysaccharide stimulation compared with their Ucp2fl/fl littermates. Together, these results demonstrate that although UCP2 regulates both metabolism and the inflammatory response of macrophages, its activity is not crucial in shaping macrophage activation in the adipose tissue during obesity-induced insulin resistance.
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Affiliation(s)
- Xanthe A M H van Dierendonck
- Nutrition, Metabolism, and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Wageningen, The Netherlands; Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | | | | | - Rinke Stienstra
- Nutrition, Metabolism, and Genomics Group, Division of Human Nutrition and Health, Wageningen University, Wageningen, The Netherlands; Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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10
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Nicholls DG. Mitochondrial proton leaks and uncoupling proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148428. [PMID: 33798544 DOI: 10.1016/j.bbabio.2021.148428] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/15/2021] [Accepted: 03/25/2021] [Indexed: 01/02/2023]
Abstract
Non-shivering thermogenesis in brown adipose tissue is mediated by uncoupling protein 1 (UCP1), which provides a carefully regulated proton re-entry pathway across the mitochondrial inner membrane operating in parallel to the ATP synthase and allowing respiration, and hence thermogenesis, to be released from the constraints of respiratory control. In the 40 years since UCP1 was first described, an extensive, and frequently contradictory, literature has accumulated, focused on the acute physiological regulation of the protein by fatty acids, purine nucleotides and possible additional factors. The purpose of this review is to examine, in detail, the experimental evidence underlying these proposed mechanisms. Emphasis will be placed on the methodologies employed and their relation to the physiological constraints under which the protein functions in the intact cell. The nature of the endogenous, UCP1-independent, proton leak will also be discussed. Finally, the troubled history of the putative novel uncoupling proteins, UCP2 and UCP3, will be evaluated.
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11
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Koshenov Z, Oflaz FE, Hirtl M, Bachkoenig OA, Rost R, Osibow K, Gottschalk B, Madreiter-Sokolowski CT, Waldeck-Weiermair M, Malli R, Graier WF. The contribution of uncoupling protein 2 to mitochondrial Ca 2+ homeostasis in health and disease - A short revisit. Mitochondrion 2020; 55:164-173. [PMID: 33069910 DOI: 10.1016/j.mito.2020.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/30/2020] [Accepted: 10/12/2020] [Indexed: 12/18/2022]
Abstract
Considering the versatile functions attributed to uncoupling protein 2 (UCP2) in health and disease, a profound understanding of the protein's molecular actions under physiological and pathophysiological conditions is indispensable. This review aims to revisit and shed light on the fundamental molecular functions of UCP2 in mitochondria, with particular emphasis on its intricate role in regulating mitochondrial calcium (Ca2+) uptake. UCP2's modulating effect on various vital processes in mitochondria makes it a crucial regulator of mitochondrial homeostasis in health and disease.
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Affiliation(s)
- Zhanat Koshenov
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Furkan E Oflaz
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Martin Hirtl
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Olaf A Bachkoenig
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Rene Rost
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Karin Osibow
- Diagnostic and Research Institute for Pathology, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria; Department of Health Sciences and Technology, ETH Zurich, Schorenstraße 16, 8603 Schwerzenbach, Switzerland
| | - Benjamin Gottschalk
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Corina T Madreiter-Sokolowski
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; Diagnostic and Research Institute for Pathology, Medical University of Graz, Neue Stiftingtalstraße 6, 8010 Graz, Austria
| | - Markus Waldeck-Weiermair
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed, Graz, Austria
| | - Wolfgang F Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria; BioTechMed, Graz, Austria.
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12
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Aguilar E, Esteves P, Sancerni T, Lenoir V, Aparicio T, Bouillaud F, Dentin R, Prip-Buus C, Ricquier D, Pecqueur C, Guilmeau S, Alves-Guerra MC. UCP2 Deficiency Increases Colon Tumorigenesis by Promoting Lipid Synthesis and Depleting NADPH for Antioxidant Defenses. Cell Rep 2020; 28:2306-2316.e5. [PMID: 31461648 PMCID: PMC6718829 DOI: 10.1016/j.celrep.2019.07.097] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 07/01/2019] [Accepted: 07/25/2019] [Indexed: 12/16/2022] Open
Abstract
Colorectal cancer (CRC) is associated with metabolic and redox perturbation. The mitochondrial transporter uncoupling protein 2 (UCP2) controls cell proliferation in vitro through the modulation of cellular metabolism, but the underlying mechanism in tumors in vivo remains unexplored. Using murine intestinal cancer models and CRC patient samples, we find higher UCP2 protein levels in tumors compared to their non-tumoral counterparts. We reveal the tumor-suppressive role of UCP2 as its deletion enhances colon and small intestinal tumorigenesis in AOM/DSS-treated and ApcMin/+ mice, respectively, and correlates with poor survival in the latter model. Mechanistically, UCP2 loss increases levels of oxidized glutathione and proteins in tumors. UCP2 deficiency alters glycolytic pathways while promoting phospholipid synthesis, thereby limiting the availability of NADPH for buffering oxidative stress. We show that UCP2 loss renders colon cells more prone to malignant transformation through metabolic reprogramming and perturbation of redox homeostasis and could favor worse outcomes in CRC. UCP2 protein expression, but not mRNA, is increased in CRC in both mice and humans UCP2 loss promotes AOM/DSS-induced CAC and ApcMin-dependent intestinal cancer UCP2 loss-induced oxidative stress contributes to increased colon tumorigenesis UCP2 deficiency drives an imbalance between lipid metabolism and NADPH homeostasis
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Affiliation(s)
- Esther Aguilar
- INSERM U1016, Institut Cochin, 75014 Paris, France; CNRS UMR 8104, 75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Pauline Esteves
- INSERM U1016, Institut Cochin, 75014 Paris, France; CNRS UMR 8104, 75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Tiphaine Sancerni
- INSERM U1016, Institut Cochin, 75014 Paris, France; CNRS UMR 8104, 75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris Cedex 13, France
| | - Véronique Lenoir
- INSERM U1016, Institut Cochin, 75014 Paris, France; CNRS UMR 8104, 75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Thomas Aparicio
- Hôpital Avicenne, HUPSSD, APHP, Université Paris 13, 93000 Bobigny, France
| | - Frédéric Bouillaud
- INSERM U1016, Institut Cochin, 75014 Paris, France; CNRS UMR 8104, 75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Renaud Dentin
- INSERM U1016, Institut Cochin, 75014 Paris, France; CNRS UMR 8104, 75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Carina Prip-Buus
- INSERM U1016, Institut Cochin, 75014 Paris, France; CNRS UMR 8104, 75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Daniel Ricquier
- INSERM U1016, Institut Cochin, 75014 Paris, France; CNRS UMR 8104, 75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Claire Pecqueur
- CRCINA - INSERM U1232, Université de Nantes, 44007 Nantes, France
| | - Sandra Guilmeau
- INSERM U1016, Institut Cochin, 75014 Paris, France; CNRS UMR 8104, 75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
| | - Marie-Clotilde Alves-Guerra
- INSERM U1016, Institut Cochin, 75014 Paris, France; CNRS UMR 8104, 75014 Paris, France; Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France.
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13
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De Marchi U, Fernandez-Martinez S, de la Fuente S, Wiederkehr A, Santo-Domingo J. Mitochondrial ion channels in pancreatic β-cells: Novel pharmacological targets for the treatment of Type 2 diabetes. Br J Pharmacol 2020; 178:2077-2095. [PMID: 32056196 PMCID: PMC8246559 DOI: 10.1111/bph.15018] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/29/2020] [Accepted: 01/31/2020] [Indexed: 12/18/2022] Open
Abstract
Pancreatic beta‐cells are central regulators of glucose homeostasis. By tightly coupling nutrient sensing and granule exocytosis, beta‐cells adjust the secretion of insulin to the circulating blood glucose levels. Failure of beta‐cells to augment insulin secretion in insulin‐resistant individuals leads progressively to impaired glucose tolerance, Type 2 diabetes, and diabetes‐related diseases. Mitochondria play a crucial role in β‐cells during nutrient stimulation, linking the metabolism of glucose and other secretagogues to the generation of signals that promote insulin secretion. Mitochondria are double‐membrane organelles containing numerous channels allowing the transport of ions across both membranes. These channels regulate mitochondrial energy production, signalling, and cell death. The mitochondria of β‐cells express ion channels whose physio/pathological role is underappreciated. Here, we describe the mitochondrial ion channels identified in pancreatic β‐cells, we further discuss the possibility of targeting specific β‐cell mitochondrial channels for the treatment of Type 2 diabetes, and we finally highlight the evidence from clinical studies. LINKED ARTICLES This article is part of a themed issue on Cellular metabolism and diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.10/issuetoc
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Affiliation(s)
| | - Silvia Fernandez-Martinez
- Division of Clinical Pharmacology and Toxicology, Centre de Recherche Clinique, HUG, Genève, Switzerland
| | - Sergio de la Fuente
- Center for Translational Medicine, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania
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Pohl EE, Jovanovic O. The Role of Phosphatidylethanolamine Adducts in Modification of the Activity of Membrane Proteins under Oxidative Stress. Molecules 2019; 24:molecules24244545. [PMID: 31842328 PMCID: PMC6943717 DOI: 10.3390/molecules24244545] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 12/09/2019] [Accepted: 12/10/2019] [Indexed: 12/11/2022] Open
Abstract
Reactive oxygen species (ROS) and their derivatives, reactive aldehydes (RAs), have been implicated in the pathogenesis of many diseases, including metabolic, cardiovascular, and inflammatory disease. Understanding how RAs can modify the function of membrane proteins is critical for the design of therapeutic approaches in the above-mentioned pathologies. Over the last few decades, direct interactions of RA with proteins have been extensively studied. Yet, few studies have been performed on the modifications of membrane lipids arising from the interaction of RAs with the lipid amino group that leads to the formation of adducts. It is even less well understood how various multiple adducts affect the properties of the lipid membrane and those of embedded membrane proteins. In this short review, we discuss a crucial role of phosphatidylethanolamine (PE) and PE-derived adducts as mediators of RA effects on membrane proteins. We propose potential PE-mediated mechanisms that explain the modulation of membrane properties and the functions of membrane transporters, channels, receptors, and enzymes. We aim to highlight this new area of research and to encourage a more nuanced investigation of the complex nature of the new lipid-mediated mechanism in the modification of membrane protein function under oxidative stress.
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Gaudry MJ, Keuper M, Jastroch M. Molecular evolution of thermogenic uncoupling protein 1 and implications for medical intervention of human disease. Mol Aspects Med 2019; 68:6-17. [DOI: 10.1016/j.mam.2019.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 06/20/2019] [Accepted: 06/21/2019] [Indexed: 12/12/2022]
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Mitochondrial Uncoupling: A Key Controller of Biological Processes in Physiology and Diseases. Cells 2019; 8:cells8080795. [PMID: 31366145 PMCID: PMC6721602 DOI: 10.3390/cells8080795] [Citation(s) in RCA: 259] [Impact Index Per Article: 51.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 07/26/2019] [Accepted: 07/28/2019] [Indexed: 12/27/2022] Open
Abstract
Mitochondrial uncoupling can be defined as a dissociation between mitochondrial membrane potential generation and its use for mitochondria-dependent ATP synthesis. Although this process was originally considered a mitochondrial dysfunction, the identification of UCP-1 as an endogenous physiological uncoupling protein suggests that the process could be involved in many other biological processes. In this review, we first compare the mitochondrial uncoupling agents available in term of mechanistic and non-specific effects. Proteins regulating mitochondrial uncoupling, as well as chemical compounds with uncoupling properties are discussed. Second, we summarize the most recent findings linking mitochondrial uncoupling and other cellular or biological processes, such as bulk and specific autophagy, reactive oxygen species production, protein secretion, cell death, physical exercise, metabolic adaptations in adipose tissue, and cell signaling. Finally, we show how mitochondrial uncoupling could be used to treat several human diseases, such as obesity, cardiovascular diseases, or neurological disorders.
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Mice overexpressing chromogranin A display hypergranulogenic adrenal glands with attenuated ATP levels contributing to the hypertensive phenotype. J Hypertens 2019; 36:1115-1128. [PMID: 29389743 DOI: 10.1097/hjh.0000000000001678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Elevated circulating chromogranin A (CHGA) is observed in human hypertension. CHGA is critical for granulogenesis and exocytosis of catecholamine stores from secretory large dense core vesicles (LDCV). This study aims to understand the morphological, molecular and phenotypic changes because of excess CHGA and the mechanistic link eventuating in hyper-adrenergic hypertension. METHODS Blood pressure and heart rate was monitored in mouse models expressing normal and elevated level of CHGA by telemetry. Catecholamine and oxidative stress radicals were measured. Adrenal ultrastructure, LDCV content and mitochondrial abundance were compared and respiration analyzed by Seahorse assay. Effect of CHGA dosage on adrenal ATP content, electron transport chain components and uncoupling protein 2 (UCP-2) were compared in vivo and in vitro. RESULTS Mice with excess-CHGA displayed hypertensive phenotype, higher heart rate and increased sympathetic tone. They had elevated plasma catecholamine and adrenal ROS levels. Excess-CHGA caused an increase in size and abundance of LDCV and adrenal mitochondria. Nonetheless, they had attenuated levels of ATP. Isolated adrenal mitochondria from mice with elevated CHGA showed higher maximal respiration rates in the presence of protonophore, which uncouples oxidative phosphorylation. Elevated CHGA resulted in overexpression of UCP2 and diminished ATP. In vitro in chromaffin cells overexpressing CHGA, concomitant increase in UCP2 protein and decreased ATP was detected. CONCLUSION Elevated CHGA expression resulted in underlying bioenergetic dysfunction in ATP production despite higher mitochondrial mass. The outcome was unregulated negative feedback of LDCV exocytosis and secretion, resulting in elevated levels of circulating catecholamine and consequently the hypertensive phenotype.
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Dieter C, Assmann TS, Costa AR, Canani LH, de Souza BM, Bauer AC, Crispim D. MiR-30e-5p and MiR-15a-5p Expressions in Plasma and Urine of Type 1 Diabetic Patients With Diabetic Kidney Disease. Front Genet 2019; 10:563. [PMID: 31249597 PMCID: PMC6582252 DOI: 10.3389/fgene.2019.00563] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/29/2019] [Indexed: 01/29/2023] Open
Abstract
Introduction Diabetic kidney disease (DKD) is a common microvascular complication that affects 40% of patients with diabetes mellitus (DM). Emerging evidence suggests a role for several microRNAs (miRNAs) in the development of DKD. In this context, miR-15a-5p and miR-30e-5p have been shown to regulate the expression of the uncoupling protein 2 (UCP2), a mitochondrial protein that decreases reactive oxygen species (ROS) formation by the mitochondria. Since ROS overproduction is a key contributor to the pathogenesis of DKD, dysregulation of these two miRNAs could be involved in DKD pathogenesis. Thus, the aim of this study was to compare the expressions of miR-15a-5p and miR-30e-5p in type 1 DM (T1DM) patients with DKD (cases) and without this complication (controls), and to perform bioinformatics analyses to investigate their putative targets and biological pathways under their regulation. Methods MiR-15a-5p and miR-30e-5p expressions were analyzed in plasma and urine of 17 T1DM controls and 23 DKD cases (12 with moderate DKD and 11 with severe DKD) using qPCR. Bioinformatics analyses were performed in Cytoscape software. Results MiR-30e-5p expression was downregulated in plasma of patients with moderate and severe DKD compared to T1DM controls. Moreover, this miRNA was also downregulated in urine of patients with severe DKD compared to the other groups. No difference was found in miR-15a-5p expression between groups. Bioinformatics analyses indicated that miR-30e-5p and miR-15a-5p regulate various genes that participate in pathways related to angiogenesis, apoptosis, cell differentiation, oxidative stress, and hypoxia. Conclusion MiR-30e-5p seems to be downregulated in plasma and urine of patients with DKD.
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Affiliation(s)
- Cristine Dieter
- Endocrine Division, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Post-Graduate Program in Medical Sciences: Endocrinology, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Taís Silveira Assmann
- Department of Food Science and Physiology, School of Pharmacy and Nutrition, University of Navarra, Pamplona, Spain
| | | | - Luís Henrique Canani
- Endocrine Division, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Post-Graduate Program in Medical Sciences: Endocrinology, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Bianca Marmontel de Souza
- Endocrine Division, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Post-Graduate Program in Medical Sciences: Endocrinology, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Andrea Carla Bauer
- Endocrine Division, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Post-Graduate Program in Medical Sciences: Endocrinology, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Nephrology Division, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Daisy Crispim
- Endocrine Division, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Post-Graduate Program in Medical Sciences: Endocrinology, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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Molecular evolution of uncoupling proteins and implications for brain function. Neurosci Lett 2018; 696:140-145. [PMID: 30582970 DOI: 10.1016/j.neulet.2018.12.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/17/2018] [Accepted: 12/18/2018] [Indexed: 01/01/2023]
Abstract
Uncoupling proteins (UCPs) belong to the mitochondrial anion carrier superfamily and catalyze important metabolic functions at the mitochondrial inner membrane. While the thermogenic role of UCP1 in brown fat of eutherian mammals is well established, the molecular functions of UCP1 in ectothermic vertebrates and of other UCP paralogs remain less clear. Here, we critically discuss the existence of brain UCPs and their potential roles. Applying phylogenetic classification of novel UCPs, we summarize the evidence for brain UCP1 among vertebrates, the role of UCP2 in specific brain areas, and the existence of brain-specific UCPs. The phylogenetic analyses and discussion on functional data should alert the scientific community that the molecular function of so-called UCP1 homologues is by far not clarified and possibly relates to neither thermogenesis nor mitochondrial uncoupling.
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Echtay KS, Bienengraeber M, Mayinger P, Heimpel S, Winkler E, Druhmann D, Frischmuth K, Kamp F, Huang SG. Uncoupling proteins: Martin Klingenberg's contributions for 40 years. Arch Biochem Biophys 2018; 657:41-55. [PMID: 30217511 DOI: 10.1016/j.abb.2018.09.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/07/2018] [Accepted: 09/10/2018] [Indexed: 12/22/2022]
Abstract
The uncoupling protein (UCP1) is a proton (H+) transporter in the mitochondrial inner membrane. By dissipating the electrochemical H+ gradient, UCP1 uncouples respiration from ATP synthesis, which drives an increase in substrate oxidation via the TCA cycle flux that generates more heat. The mitochondrial uncoupling-mediated non-shivering thermogenesis in brown adipose tissue is vital primarily to mammals, such as rodents and new-born humans, but more recently additional functions in adult humans have been described. UCP1 is regulated by β-adrenergic receptors through the sympathetic nervous system and at the molecular activity level by nucleotides and fatty acid to meet thermogenesis needs. The discovery of novel UCP homologs has greatly contributed to the understanding of human diseases, such as obesity and diabetes. In this article, we review the progress made towards the molecular mechanism and function of the UCPs, in particular focusing on the influential contributions from Martin Klingenberg's laboratory. Because all members of the UCP family are potentially promising drug targets, we also present and discuss possible approaches and methods for UCP-related drug discovery.
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Affiliation(s)
- Karim S Echtay
- Department of Biomedical Sciences, Faculty of Medicine and Medical Sciences, University of Balamand, P.O. Box: 100, Tripoli, Lebanon
| | - Martin Bienengraeber
- Departments of Anesthesiology and Pharmacology, Medical College of Wisconsin, Milwaukee, USA
| | - Peter Mayinger
- Division of Nephrology & Hypertension and Department of Cell, Developmental & Cancer Biology, Oregon Health & Science University, 2730 SW Moody Ave, Portland, OR, 97201, USA
| | - Simone Heimpel
- Campus of Applied Science, University of Applied Sciences Würzburg-Schweinfurt, Münzstraße 12, D-97070, Würzburg, Germany
| | - Edith Winkler
- Institute of Physical Biochemistry, University of Munich, Schillerstrasse 44, D-80336, Munich, Germany
| | - Doerthe Druhmann
- Institute of Physical Biochemistry, University of Munich, Schillerstrasse 44, D-80336, Munich, Germany
| | - Karina Frischmuth
- Institute of Physical Biochemistry, University of Munich, Schillerstrasse 44, D-80336, Munich, Germany
| | - Frits Kamp
- Institute of Physical Biochemistry, University of Munich, Schillerstrasse 44, D-80336, Munich, Germany
| | - Shu-Gui Huang
- BioAssay Systems, 3191 Corporate Place, Hayward, CA, 94545, USA.
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Ježek P, Holendová B, Garlid KD, Jabůrek M. Mitochondrial Uncoupling Proteins: Subtle Regulators of Cellular Redox Signaling. Antioxid Redox Signal 2018; 29:667-714. [PMID: 29351723 PMCID: PMC6071544 DOI: 10.1089/ars.2017.7225] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE Mitochondria are the energetic, metabolic, redox, and information signaling centers of the cell. Substrate pressure, mitochondrial network dynamics, and cristae morphology state are integrated by the protonmotive force Δp or its potential component, ΔΨ, which are attenuated by proton backflux into the matrix, termed uncoupling. The mitochondrial uncoupling proteins (UCP1-5) play an eminent role in the regulation of each of the mentioned aspects, being involved in numerous physiological events including redox signaling. Recent Advances: UCP2 structure, including purine nucleotide and fatty acid (FA) binding sites, strongly support the FA cycling mechanism: UCP2 expels FA anions, whereas uncoupling is achieved by the membrane backflux of protonated FA. Nascent FAs, cleaved by phospholipases, are preferential. The resulting Δp dissipation decreases superoxide formation dependent on Δp. UCP-mediated antioxidant protection and its impairment are expected to play a major role in cell physiology and pathology. Moreover, UCP2-mediated aspartate, oxaloacetate, and malate antiport with phosphate is expected to alter metabolism of cancer cells. CRITICAL ISSUES A wide range of UCP antioxidant effects and participations in redox signaling have been reported; however, mechanisms of UCP activation are still debated. Switching off/on the UCP2 protonophoretic function might serve as redox signaling either by employing/releasing the extra capacity of cell antioxidant systems or by directly increasing/decreasing mitochondrial superoxide sources. Rapid UCP2 degradation, FA levels, elevation of purine nucleotides, decreased Mg2+, or increased pyruvate accumulation may initiate UCP-mediated redox signaling. FUTURE DIRECTIONS Issues such as UCP2 participation in glucose sensing, neuronal (synaptic) function, and immune cell activation should be elucidated. Antioxid. Redox Signal. 29, 667-714.
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Affiliation(s)
- Petr Ježek
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
| | - Blanka Holendová
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
| | - Keith D Garlid
- 2 UCLA Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA , Los Angeles, California
| | - Martin Jabůrek
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
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Cadenas S. Mitochondrial uncoupling, ROS generation and cardioprotection. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:940-950. [DOI: 10.1016/j.bbabio.2018.05.019] [Citation(s) in RCA: 238] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 05/11/2018] [Accepted: 05/29/2018] [Indexed: 12/31/2022]
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Tian XY, Ma S, Tse G, Wong WT, Huang Y. Uncoupling Protein 2 in Cardiovascular Health and Disease. Front Physiol 2018; 9:1060. [PMID: 30116205 PMCID: PMC6082951 DOI: 10.3389/fphys.2018.01060] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Accepted: 07/16/2018] [Indexed: 12/22/2022] Open
Abstract
Uncoupling protein 2 (UCP2) belongs to the family of mitochondrial anion carrier proteins. It uncouples oxygen consumption from ATP synthesis. UCP2 is ubiquitously expressed in most cell types to reduce oxidative stress. It is tightly regulated at the transcriptional, translational, and post-translational levels. UCP2 in the cardiovascular system is being increasingly recognized as an important molecule to defend against various stress signals such as oxidative stress in the pathology of vascular dysfunction, atherosclerosis, hypertension, and cardiac injuries. UCP2 protects against cellular dysfunction through reducing mitochondrial oxidative stress and modulation of mitochondrial function. In view of the different functions of UCP2 in various cell types that contribute to whole body homeostasis, cell type-specific modification of UCP2 expression may offer a better approach to help understanding how UCP2 governs mitochondrial function, reactive oxygen species production and transmembrane proton leak and how dysfunction of UCP2 participates in the development of cardiovascular diseases. This review article provided an update on the physiological regulation of UCP2 in the cardiovascular system, and also discussed the involvement of UCP2 deficiency and associated oxidative stress in the pathogenesis of several common cardiovascular diseases. Drugs targeting UCP2 expression and activity might serve another effective strategy to ameliorate cardiovascular dysfunction. However, more detailed mechanistic study will be needed to dissect the role of UCP2, the regulation of UCP2 expression, and the cellular responses to the changes of UCP2 expression in normal and stressed situations at different stages of cardiovascular diseases.
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Affiliation(s)
- Xiao Yu Tian
- School of Biomedical Sciences, Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Shuangtao Ma
- Division of Nanomedicine and Molecular Intervention, Department of Medicine, Michigan State University, East Lansing, MI, United States
| | - Gary Tse
- Department of Medicine and Therapeutics, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Wing Tak Wong
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Yu Huang
- School of Biomedical Sciences, Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
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Friederich-Persson M, Persson P, Hansell P, Palm F. Deletion of Uncoupling Protein-2 reduces renal mitochondrial leak respiration, intrarenal hypoxia and proteinuria in a mouse model of type 1 diabetes. Acta Physiol (Oxf) 2018; 223:e13058. [PMID: 29480974 DOI: 10.1111/apha.13058] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 02/19/2018] [Accepted: 02/19/2018] [Indexed: 12/26/2022]
Abstract
AIM Uncoupling protein-2 (UCP-2) can induce mitochondrial uncoupling in the diabetic kidney. Although mitochondrial uncoupling reduces oxidative stress originating from the mitochondria and can be regarded as a protective mechanism, the increased oxygen consumption occurring secondarily to increased mitochondria uncoupling, that is leak respiration, may contribute to kidney tissue hypoxia. Using UCP-2-/- mice, we tested the hypothesis that UCP-2-mediated leak respiration is important for the development of diabetes-induced intrarenal hypoxia and proteinuria. METHODS Kidney function, in vivo oxygen metabolism, urinary protein leakage and mitochondrial function were determined in wild-type and UCP-2-/- mice during normoglycaemia and 2 weeks after diabetes induction. RESULTS Diabetic wild-type mice displayed mitochondrial leak respiration, pronounced intrarenal hypoxia, proteinuria and increased urinary KIM-1 excretion. However, diabetic UCP-2-/- mice did not develop increased mitochondrial leak respiration and presented with normal intrarenal oxygen levels, urinary protein and KIM-1 excretion. CONCLUSION Although functioning as an antioxidant system, mitochondria uncoupling is always in co-occurrence with increased oxygen consumption, that is leak respiration; a potentially detrimental side effect as it can result in kidney tissue hypoxia; an acknowledged unifying pathway to nephropathy. Indeed, this study demonstrates a novel mechanism in which UCP-2-mediated mitochondrial leak respiration is necessary for the development of diabetes-induced intrarenal tissue hypoxia and proteinuria.
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Affiliation(s)
- M. Friederich-Persson
- Division of Integrative Physiology; Department of Medical Cell Biology; Uppsala University; Uppsala Sweden
| | - P. Persson
- Division of Integrative Physiology; Department of Medical Cell Biology; Uppsala University; Uppsala Sweden
| | - P. Hansell
- Division of Integrative Physiology; Department of Medical Cell Biology; Uppsala University; Uppsala Sweden
| | - F. Palm
- Division of Integrative Physiology; Department of Medical Cell Biology; Uppsala University; Uppsala Sweden
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Chen K, Xu Z, Liu Y, Wang Z, Li Y, Xu X, Chen C, Xia T, Liao Q, Yao Y, Zeng C, He D, Yang Y, Tan T, Yi J, Zhou J, Zhu H, Ma J, Zeng C. Irisin protects mitochondria function during pulmonary ischemia/reperfusion injury. Sci Transl Med 2018; 9:9/418/eaao6298. [PMID: 29187642 DOI: 10.1126/scitranslmed.aao6298] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 08/10/2017] [Accepted: 10/20/2017] [Indexed: 12/13/2022]
Abstract
Limb remote ischemic preconditioning (RIPC) is an effective means of protection against ischemia/reperfusion (IR)-induced injury to multiple organs. Many studies are focused on identifying endocrine mechanisms that underlie the cross-talk between muscle and RIPC-mediated organ protection. We report that RIPC releases irisin, a myokine derived from the extracellular portion of fibronectin domain-containing 5 protein (FNDC5) in skeletal muscle, to protect against injury to the lung. Human patients with neonatal respiratory distress syndrome show reduced concentrations of irisin in the serum and increased irisin concentrations in the bronchoalveolar lavage fluid, suggesting transfer of irisin from circulation to the lung under physiologic stress. In mice, application of brief periods of ischemia preconditioning stimulates release of irisin into circulation and transfer of irisin to the lung subjected to IR injury. Irisin, via lipid raft-mediated endocytosis, enters alveolar cells and targets mitochondria. Interaction between irisin and mitochondrial uncoupling protein 2 (UCP2) allows for prevention of IR-induced oxidative stress and preservation of mitochondrial function. Animal model studies show that intravenous administration of exogenous irisin protects against IR-induced injury to the lung via improvement of mitochondrial function, whereas in UCP2-deficient mice or in the presence of a UCP2 inhibitor, the protective effect of irisin is compromised. These results demonstrate that irisin is a myokine that facilitates RIPC-mediated lung protection. Targeting the action of irisin in mitochondria presents a potential therapeutic intervention for pulmonary IR injury.
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Affiliation(s)
- Ken Chen
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China.,Department of Cardiology, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Zaicheng Xu
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Yukai Liu
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Zhen Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Yu Li
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Xuefei Xu
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Caiyu Chen
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Tianyang Xia
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Qiao Liao
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Yonggang Yao
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Cindy Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Duofen He
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China.,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
| | - Yongjian Yang
- Department of Cardiology, Chengdu Military General Hospital, Chengdu, Sichuan 610083, P.R. China
| | - Tao Tan
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Jianxun Yi
- Department of Physiology, Kansas City University, Kansas City, MO 64106, USA
| | - Jingsong Zhou
- Department of Physiology, Kansas City University, Kansas City, MO 64106, USA
| | - Hua Zhu
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Jianjie Ma
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA.
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, P.R. China. .,Chongqing Institute of Cardiology, Chongqing 400042, P.R. China
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Szelechowski M, Amoedo N, Obre E, Léger C, Allard L, Bonneu M, Claverol S, Lacombe D, Oliet S, Chevallier S, Le Masson G, Rossignol R. Metabolic Reprogramming in Amyotrophic Lateral Sclerosis. Sci Rep 2018; 8:3953. [PMID: 29500423 PMCID: PMC5834494 DOI: 10.1038/s41598-018-22318-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 02/21/2018] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial dysfunction in the spinal cord is a hallmark of amyotrophic lateral sclerosis (ALS), but the neurometabolic alterations during early stages of the disease remain unknown. Here, we investigated the bioenergetic and proteomic changes in ALS mouse motor neurons and patients' skin fibroblasts. We first observed that SODG93A mice presymptomatic motor neurons display alterations in the coupling efficiency of oxidative phosphorylation, along with fragmentation of the mitochondrial network. The proteome of presymptomatic ALS mice motor neurons also revealed a peculiar metabolic signature with upregulation of most energy-transducing enzymes, including the fatty acid oxidation (FAO) and the ketogenic components HADHA and ACAT2, respectively. Accordingly, FAO inhibition altered cell viability specifically in ALS mice motor neurons, while uncoupling protein 2 (UCP2) inhibition recovered cellular ATP levels and mitochondrial network morphology. These findings suggest a novel hypothesis of ALS bioenergetics linking FAO and UCP2. Lastly, we provide a unique set of data comparing the molecular alterations found in human ALS patients' skin fibroblasts and SODG93A mouse motor neurons, revealing conserved changes in protein translation, folding and assembly, tRNA aminoacylation and cell adhesion processes.
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Affiliation(s)
- M Szelechowski
- INSERM U1215, Neurocentre Magendie, 33077, Bordeaux, cedex, France
- Bordeaux University, 33000, Bordeaux, France
| | - N Amoedo
- Bordeaux University, 33000, Bordeaux, France
- INSERM U1211, MRGM, 33000, Bordeaux, France
| | - E Obre
- CELLOMET, Center of Functional Genomics (CGFB), 146 Rue Léo Saignat, 33000, Bordeaux, France
| | - C Léger
- INSERM U1215, Neurocentre Magendie, 33077, Bordeaux, cedex, France
- Bordeaux University, 33000, Bordeaux, France
| | - L Allard
- INSERM U1215, Neurocentre Magendie, 33077, Bordeaux, cedex, France
- Bordeaux University, 33000, Bordeaux, France
| | - M Bonneu
- Bordeaux University, 33000, Bordeaux, France
- Center of Functional Genomics (CGFB), Proteomic Facility, Bordeaux University, 33000, Bordeaux, France
| | - S Claverol
- Bordeaux University, 33000, Bordeaux, France
- Center of Functional Genomics (CGFB), Proteomic Facility, Bordeaux University, 33000, Bordeaux, France
| | - D Lacombe
- Bordeaux University, 33000, Bordeaux, France
- INSERM U1211, MRGM, 33000, Bordeaux, France
| | - S Oliet
- INSERM U1215, Neurocentre Magendie, 33077, Bordeaux, cedex, France
- Bordeaux University, 33000, Bordeaux, France
| | - S Chevallier
- INSERM U1215, Neurocentre Magendie, 33077, Bordeaux, cedex, France
- Bordeaux University, 33000, Bordeaux, France
| | - G Le Masson
- INSERM U1215, Neurocentre Magendie, 33077, Bordeaux, cedex, France.
- Bordeaux University, 33000, Bordeaux, France.
| | - R Rossignol
- Bordeaux University, 33000, Bordeaux, France.
- INSERM U1211, MRGM, 33000, Bordeaux, France.
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27
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Uncoupling protein 1 controls reactive oxygen species in brown adipose tissue. Proc Natl Acad Sci U S A 2017; 114:7744-7746. [PMID: 28710335 DOI: 10.1073/pnas.1709064114] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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28
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Yan P, Chen K, Wang Q, Yang D, Li D, Yang Y. UCP-2 is involved in angiotensin-II-induced abdominal aortic aneurysm in apolipoprotein E-knockout mice. PLoS One 2017; 12:e0179743. [PMID: 28683125 PMCID: PMC5500278 DOI: 10.1371/journal.pone.0179743] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Accepted: 06/02/2017] [Indexed: 02/07/2023] Open
Abstract
UCP-2 shows an important role in modulating of mitochondrial membrane potential and cell apoptosis. Whether or not UCP-2 could been a critical factor in preventing AAA formation is not known. We report that UCP-2 protein and mRNA expression were significantly higher in Ang-Ⅱ-induced AAA of mice. The incident rate of AAA in UCP-2-/-ApoE-/- mice after Ang-Ⅱtreatment was higher than the rate in the UCP-2+/+ApoE-/- mice. The abdominal aorta from UCP-2-/-ApoE-/- mice showed the medial hypertrophy, fragmentation of elastic lamellas and depletion of α-SMA. The NADPH oxidase activity and level of MDA was significantly higher in UCP-2-/-ApoE-/- mice than UCP-2+/+ApoE-/- or WT mice. Besides, the SOD activity is increased in UCP-2+/+ApoE-/- mice as compared with WT mice, whereas deficiency of UCP-2 decreased the increasing SOD activity in Ang-Ⅱ treated ApoE-/- mice. UCP-2 knockout up-regulated the MMP2 and MMP9 expression in aortic aneurysm. Ang-Ⅱ induced apoptosis of VSMCs was increased in UCP-2-/-ApoE-/- mice. And the expression of eNOS in vascular tissue from UCP-2-/-ApoE-/- mice is lower than WT and UCP-2+/+ApoE-/- mice. This study provides a mechanism by which UCP-2, via anti-oxidants and anti-apoptosis, participates in the preventing of AAA formation.
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MESH Headings
- Actins/genetics
- Actins/metabolism
- Angiotensin II/pharmacology
- Animals
- Aorta, Abdominal/drug effects
- Aorta, Abdominal/metabolism
- Aorta, Abdominal/pathology
- Aortic Aneurysm, Abdominal/chemically induced
- Aortic Aneurysm, Abdominal/genetics
- Aortic Aneurysm, Abdominal/metabolism
- Aortic Aneurysm, Abdominal/pathology
- Apolipoproteins E/deficiency
- Apolipoproteins E/genetics
- Apoptosis/drug effects
- Endothelial Cells/drug effects
- Endothelial Cells/metabolism
- Endothelial Cells/pathology
- Gene Expression Regulation
- Malondialdehyde/metabolism
- Matrix Metalloproteinase 2/genetics
- Matrix Metalloproteinase 2/metabolism
- Matrix Metalloproteinase 9/genetics
- Matrix Metalloproteinase 9/metabolism
- Membrane Potential, Mitochondrial/drug effects
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- NADPH Oxidases/genetics
- NADPH Oxidases/metabolism
- Nitric Oxide Synthase Type III/genetics
- Nitric Oxide Synthase Type III/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Signal Transduction
- Superoxide Dismutase/genetics
- Superoxide Dismutase/metabolism
- Uncoupling Protein 2/deficiency
- Uncoupling Protein 2/genetics
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Affiliation(s)
- Peng Yan
- Department of Cardiology, Chengdu Military General Hospital, Chengdu, Sichuan, P.R. China
| | - Ken Chen
- Department of Cardiology, Chengdu Military General Hospital, Chengdu, Sichuan, P.R. China
| | - Qiang Wang
- Department of Cardiology, Chengdu Military General Hospital, Chengdu, Sichuan, P.R. China
| | - Dachun Yang
- Department of Cardiology, Chengdu Military General Hospital, Chengdu, Sichuan, P.R. China
| | - De Li
- Department of Cardiology, Chengdu Military General Hospital, Chengdu, Sichuan, P.R. China
| | - Yongjian Yang
- Department of Cardiology, Chengdu Military General Hospital, Chengdu, Sichuan, P.R. China
- * E-mail:
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29
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Crichton PG, Lee Y, Kunji ERS. The molecular features of uncoupling protein 1 support a conventional mitochondrial carrier-like mechanism. Biochimie 2017; 134:35-50. [PMID: 28057583 PMCID: PMC5395090 DOI: 10.1016/j.biochi.2016.12.016] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 12/24/2016] [Indexed: 12/14/2022]
Abstract
Uncoupling protein 1 (UCP1) is an integral membrane protein found in the mitochondrial inner membrane of brown adipose tissue, and facilitates the process of non-shivering thermogenesis in mammals. Its activation by fatty acids, which overcomes its inhibition by purine nucleotides, leads to an increase in the proton conductance of the inner mitochondrial membrane, short-circuiting the mitochondrion to produce heat rather than ATP. Despite 40 years of intense research, the underlying molecular mechanism of UCP1 is still under debate. The protein belongs to the mitochondrial carrier family of transporters, which have recently been shown to utilise a domain-based alternating-access mechanism, cycling between a cytoplasmic and matrix state to transport metabolites across the inner membrane. Here, we review the protein properties of UCP1 and compare them to those of mitochondrial carriers. UCP1 has the same structural fold as other mitochondrial carriers and, in contrast to past claims, is a monomer, binding one purine nucleotide and three cardiolipin molecules tightly. The protein has a single substrate binding site, which is similar to those of the dicarboxylate and oxoglutarate carriers, but also contains a proton binding site and several hydrophobic residues. As found in other mitochondrial carriers, UCP1 has two conserved salt bridge networks on either side of the central cavity, which regulate access to the substrate binding site in an alternating way. The conserved domain structures and mobile inter-domain interfaces are consistent with an alternating access mechanism too. In conclusion, UCP1 has retained all of the key features of mitochondrial carriers, indicating that it operates by a conventional carrier-like mechanism.
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Affiliation(s)
- Paul G Crichton
- Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom.
| | - Yang Lee
- Laboratory of Molecular Biology, Medical Research Council, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Edmund R S Kunji
- Mitochondrial Biology Unit, Medical Research Council, Cambridge Biomedical Campus, Wellcome Trust, MRC Building, Hills Road, Cambridge CB2 0XY, United Kingdom.
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30
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The conserved regulation of mitochondrial uncoupling proteins: From unicellular eukaryotes to mammals. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1858:21-33. [PMID: 27751905 DOI: 10.1016/j.bbabio.2016.10.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/29/2016] [Accepted: 10/13/2016] [Indexed: 12/19/2022]
Abstract
Uncoupling proteins (UCPs) belong to the mitochondrial anion carrier protein family and mediate regulated proton leak across the inner mitochondrial membrane. Free fatty acids, aldehydes such as hydroxynonenal, and retinoids activate UCPs. However, there are some controversies about the effective action of retinoids and aldehydes alone; thus, only free fatty acids are commonly accepted positive effectors of UCPs. Purine nucleotides such as GTP inhibit UCP-mediated mitochondrial proton leak. In turn, membranous coenzyme Q may play a role as a redox state-dependent metabolic sensor that modulates the complete activation/inhibition of UCPs. Such regulation has been observed for UCPs in microorganisms, plant and animal UCP1 homologues, and UCP1 in mammalian brown adipose tissue. The origin of UCPs is still under debate, but UCP homologues have been identified in all systematic groups of eukaryotes. Despite the differing levels of amino acid/DNA sequence similarities, functional studies in unicellular and multicellular organisms, from amoebae to mammals, suggest that the mechanistic regulation of UCP activity is evolutionarily well conserved. This review focuses on the regulatory feedback loops of UCPs involving free fatty acids, aldehydes, retinoids, purine nucleotides, and coenzyme Q (particularly its reduction level), which may derive from the early stages of evolution as UCP first emerged.
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31
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Gill KS, Fernandes P, O'Donovan TR, McKenna SL, Doddakula KK, Power DG, Soden DM, Forde PF. Glycolysis inhibition as a cancer treatment and its role in an anti-tumour immune response. Biochim Biophys Acta Rev Cancer 2016; 1866:87-105. [PMID: 27373814 DOI: 10.1016/j.bbcan.2016.06.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 06/29/2016] [Accepted: 06/30/2016] [Indexed: 12/23/2022]
Abstract
Increased glycolysis is the main source of energy supply in cancer cells that use this metabolic pathway for ATP generation. Altered energy metabolism is a biochemical fingerprint of cancer cells that represents one of the "hallmarks of cancer". The immune system can prevent tumour growth by eliminating cancer cells but this editing process ultimately results in poorly immunogenic cells remaining allowing for unchallenged tumour growth. In this review we look at the glycolysis pathway as a target for cancer treatments. We also examine the interplay between the glycolysis modulation and the immune response as an anti-cancer therapy.
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Affiliation(s)
- Kheshwant S Gill
- Cork Cancer Research Centre, Western Gateway Building, University College Cork, Cork, Ireland; Cardiothoracic Surgery Department, Cork University Hospital, Cork, Ireland
| | - Philana Fernandes
- Cork Cancer Research Centre, Western Gateway Building, University College Cork, Cork, Ireland
| | - Tracey R O'Donovan
- Cork Cancer Research Centre, Western Gateway Building, University College Cork, Cork, Ireland
| | - Sharon L McKenna
- Cork Cancer Research Centre, Western Gateway Building, University College Cork, Cork, Ireland
| | | | - Derek G Power
- Cork Cancer Research Centre, Western Gateway Building, University College Cork, Cork, Ireland; Department of Medical Oncology, Mercy University Hospital, Grenville Place, Cork, Ireland
| | - Declan M Soden
- Cork Cancer Research Centre, Western Gateway Building, University College Cork, Cork, Ireland
| | - Patrick F Forde
- Cork Cancer Research Centre, Western Gateway Building, University College Cork, Cork, Ireland.
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32
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UCPs, at the interface between bioenergetics and metabolism. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2443-56. [PMID: 27091404 DOI: 10.1016/j.bbamcr.2016.04.013] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 04/11/2016] [Accepted: 04/12/2016] [Indexed: 01/25/2023]
Abstract
The first member of the uncoupling protein (UCP) family, brown adipose tissue uncoupling protein 1 (UCP1), was identified in 1976. Twenty years later, two closely related proteins, UCP2 and UCP3, were described in mammals. Homologs of these proteins exist in other organisms, including plants. Uncoupling refers to a deterioration of energy conservation between substrate oxidation and ADP phosphorylation. Complete energy conservation loss would be fatal but fine-tuning can be beneficial for processes such as thermogenesis, redox control, and prevention of mitochondrial ROS release. The coupled/uncoupled state of mitochondria is related to the permeability of the inner membrane and the proton transport mediated by activated UCPs underlies the uncoupling activity of these proteins. Proton transport by UCP1 is activated by fatty acids and this ensures thermogenesis. In vivo in absence of this activation UCP1 remains inhibited with no transport activity. A similar situation now seems unlikely for UCP2 and UCP3 and while activation of their proton transport has been described its physiological relevance remains uncertain and their influence can be envisaged as a result of another transport pathway that takes place in the absence of activation. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou.
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Uncoupling Protein 2 Increases Susceptibility to Lipopolysaccharide-Induced Acute Lung Injury in Mice. Mediators Inflamm 2016; 2016:9154230. [PMID: 27057102 PMCID: PMC4761398 DOI: 10.1155/2016/9154230] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 12/14/2015] [Accepted: 01/06/2016] [Indexed: 12/15/2022] Open
Abstract
Uncoupling protein 2 (UCP2) is upregulated in patients with systemic inflammation and infection, but its functional role is unclear. We up- or downregulated UCP2 expression using UCP2 recombinant adenovirus or the UCP2 inhibitor, genipin, in lungs of mice, and investigated the mechanisms of UCP2 in ALI. UCP2 overexpression in mouse lungs increased LPS-induced pathological changes, lung permeability, lung inflammation, and lowered survival rates. Furthermore, ATP levels and mitochondrial membrane potential were decreased, while reactive oxygen species production was increased. Additionally, mitogen-activated protein kinases (MAPKs) activity was elevated, which increased the sensitivity to LPS-induced apoptosis and inflammation. LPS-induced apoptosis and release of inflammatory factors were alleviated by pretreatment of the Jun N-terminal kinase (JNK) inhibitor SP600125 or the p38 MAPK inhibitor SB203580, but not by the extracellular signal-regulated kinase (ERK) inhibitor PD98059 in UCP2-overexpressing mice. On the other hand, LPS-induced alveolar epithelial cell death and inflammation were attenuated by genipin. In conclusion, UCP2 increased susceptibility to LPS-induced cell death and pulmonary inflammation, most likely via ATP depletion and activation of MAPK signaling following ALI in mice.
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34
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Akhmedov AT, Rybin V, Marín-García J. Mitochondrial oxidative metabolism and uncoupling proteins in the failing heart. Heart Fail Rev 2015; 20:227-49. [PMID: 25192828 DOI: 10.1007/s10741-014-9457-4] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Despite significant progress in cardiovascular medicine, myocardial ischemia and infarction, progressing eventually to the final end point heart failure (HF), remain the leading cause of morbidity and mortality in the USA. HF is a complex syndrome that results from any structural or functional impairment in ventricular filling or blood ejection. Ultimately, the heart's inability to supply the body's tissues with enough blood may lead to death. Mechanistically, the hallmarks of the failing heart include abnormal energy metabolism, increased production of reactive oxygen species (ROS) and defects in excitation-contraction coupling. HF is a highly dynamic pathological process, and observed alterations in cardiac metabolism and function depend on the disease progression. In the early stages, cardiac remodeling characterized by normal or slightly increased fatty acid (FA) oxidation plays a compensatory, cardioprotective role. However, upon progression of HF, FA oxidation and mitochondrial oxidative activity are decreased, resulting in a significant drop in cardiac ATP levels. In HF, as a compensatory response to decreased oxidative metabolism, glucose uptake and glycolysis are upregulated, but this upregulation is not sufficient to compensate for a drop in ATP production. Elevated mitochondrial ROS generation and ROS-mediated damage, when they overwhelm the cellular antioxidant defense system, induce heart injury and contribute to the progression of HF. Mitochondrial uncoupling proteins (UCPs), which promote proton leak across the inner mitochondrial membrane, have emerged as essential regulators of mitochondrial membrane potential, respiratory activity and ROS generation. Although the physiological role of UCP2 and UCP3, expressed in the heart, has not been clearly established, increasing evidence suggests that these proteins by promoting mild uncoupling could reduce mitochondrial ROS generation and cardiomyocyte apoptosis and ameliorate thereby myocardial function. Further investigation on the alterations in cardiac UCP activity and regulation will advance our understanding of their physiological roles in the healthy and diseased heart and also may facilitate the development of novel and more efficient therapies.
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Affiliation(s)
- Alexander T Akhmedov
- The Molecular Cardiology and Neuromuscular Institute, 75 Raritan Avenue, Highland Park, NJ, 08904, USA
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35
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Donadelli M, Dando I, Dalla Pozza E, Palmieri M. Mitochondrial uncoupling protein 2 and pancreatic cancer: A new potential target therapy. World J Gastroenterol 2015; 21:3232-3238. [PMID: 25805929 PMCID: PMC4363752 DOI: 10.3748/wjg.v21.i11.3232] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 12/18/2014] [Accepted: 02/05/2015] [Indexed: 02/06/2023] Open
Abstract
Overall 5-years survival of pancreatic cancer patients is nearly 5%, making this cancer type one of the most lethal neoplasia. Furthermore, the incidence rate of pancreatic cancer has a growing trend that determines a constant increase in the number of deceases caused by this pathology. The poor prognosis of pancreatic cancer is mainly caused by delayed diagnosis, early metastasis of tumor, and resistance to almost all tested cytotoxic drugs. In this respect, the identification of novel potential targets for new and efficient therapies should be strongly encouraged in order to improve the clinical management of pancreatic cancer. Some studies have shown that the mitochondrial uncoupling protein 2 (UCP2) is over-expressed in pancreatic cancer as compared to adjacent normal tissues. In addition, recent discoveries established a key role of UCP2 in protecting cancer cells from an excessive production of mitochondrial superoxide ions and in the promotion of cancer cell metabolic reprogramming, including aerobic glycolysis stimulation, promotion of cancer progression. These observations together with the demonstration that UCP2 repression can synergize with standard chemotherapy to inhibit pancreatic cancer cell growth provide the molecular rationale to consider UCP2 as a potential therapeutic target for pancreatic cancer. In this editorial, recent advances describing the relationship between cancer development and mitochondrial UCP2 activity are critically provided.
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36
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Kukat A, Dogan SA, Edgar D, Mourier A, Jacoby C, Maiti P, Mauer J, Becker C, Senft K, Wibom R, Kudin AP, Hultenby K, Flögel U, Rosenkranz S, Ricquier D, Kunz WS, Trifunovic A. Loss of UCP2 attenuates mitochondrial dysfunction without altering ROS production and uncoupling activity. PLoS Genet 2014; 10:e1004385. [PMID: 24945157 PMCID: PMC4063685 DOI: 10.1371/journal.pgen.1004385] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 04/02/2014] [Indexed: 11/18/2022] Open
Abstract
Although mitochondrial dysfunction is often accompanied by excessive reactive oxygen species (ROS) production, we previously showed that an increase in random somatic mtDNA mutations does not result in increased oxidative stress. Normal levels of ROS and oxidative stress could also be a result of an active compensatory mechanism such as a mild increase in proton leak. Uncoupling protein 2 (UCP2) was proposed to play such a role in many physiological situations. However, we show that upregulation of UCP2 in mtDNA mutator mice is not associated with altered proton leak kinetics or ROS production, challenging the current view on the role of UCP2 in energy metabolism. Instead, our results argue that high UCP2 levels allow better utilization of fatty acid oxidation resulting in a beneficial effect on mitochondrial function in heart, postponing systemic lactic acidosis and resulting in longer lifespan in these mice. This study proposes a novel mechanism for an adaptive response to mitochondrial cardiomyopathy that links changes in metabolism to amelioration of respiratory chain deficiency and longer lifespan.
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Affiliation(s)
- Alexandra Kukat
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, Cologne, Germany
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Sukru Anil Dogan
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, Cologne, Germany
| | - Daniel Edgar
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Arnaud Mourier
- Max Planck Institute for Biology of Aging, Cologne, Germany
| | - Christoph Jacoby
- Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Priyanka Maiti
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, Cologne, Germany
| | - Jan Mauer
- Max Planck Institute for Neurological Research, Cologne, Germany
| | - Christina Becker
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, Cologne, Germany
| | - Katharina Senft
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, Cologne, Germany
| | - Rolf Wibom
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Alexei P. Kudin
- Department of Epileptology, University of Bonn, Bonn, Germany
| | - Kjell Hultenby
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Ulrich Flögel
- Department of Cardiovascular Physiology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Stephan Rosenkranz
- Department III of Internal Medicine, University of Cologne, Cologne, Germany
- Cologne Cardiovascular Research Center (CCRC) and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Daniel Ricquier
- University Paris Descartes, Faculty of Medicine, CNRS FRE3210, Paris, France
| | - Wolfram S. Kunz
- Department of Epileptology, University of Bonn, Bonn, Germany
| | - Aleksandra Trifunovic
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, Cologne, Germany
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
- Cologne Cardiovascular Research Center (CCRC) and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
- * E-mail:
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Esteves P, Pecqueur C, Ransy C, Esnous C, Lenoir V, Bouillaud F, Bulteau AL, Lombès A, Prip-Buus C, Ricquier D, Alves-Guerra MC. Mitochondrial retrograde signaling mediated by UCP2 inhibits cancer cell proliferation and tumorigenesis. Cancer Res 2014; 74:3971-82. [PMID: 24853548 DOI: 10.1158/0008-5472.can-13-3383] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cancer cells tilt their energy production away from oxidative phosphorylation (OXPHOS) toward glycolysis during malignant progression, even when aerobic metabolism is available. Reversing this phenomenon, known as the Warburg effect, may offer a generalized anticancer strategy. In this study, we show that overexpression of the mitochondrial membrane transport protein UCP2 in cancer cells is sufficient to restore a balance toward oxidative phosphorylation and to repress malignant phenotypes. Altered expression of glycolytic and oxidative enzymes mediated the effects of this metabolic shift. Notably, UCP2 overexpression increased signaling from the master energy-regulating kinase, adenosine monophosphate-activated protein kinase, while downregulating expression of hypoxia-induced factor. In support of recent new evidence about UCP2 function, we found that UCP2 did not function in this setting as a membrane potential uncoupling protein, but instead acted to control routing of mitochondria substrates. Taken together, our results define a strategy to reorient mitochondrial function in cancer cells toward OXPHOS that restricts their malignant phenotype.
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Affiliation(s)
- Pauline Esteves
- Authors' Affiliations: Inserm, U1016, Institut Cochin; CNRS, UMR 8104; Université Paris Descartes, Sorbonne Paris Cité, Paris
| | - Claire Pecqueur
- CRCNA-UMR 892 INSERM-6299 CNRS; and Faculté de Médecine, Université de Nantes, Nantes, France
| | - Céline Ransy
- Authors' Affiliations: Inserm, U1016, Institut Cochin; CNRS, UMR 8104; Université Paris Descartes, Sorbonne Paris Cité, Paris
| | - Catherine Esnous
- Authors' Affiliations: Inserm, U1016, Institut Cochin; CNRS, UMR 8104; Université Paris Descartes, Sorbonne Paris Cité, Paris
| | - Véronique Lenoir
- Authors' Affiliations: Inserm, U1016, Institut Cochin; CNRS, UMR 8104; Université Paris Descartes, Sorbonne Paris Cité, Paris
| | - Frédéric Bouillaud
- Authors' Affiliations: Inserm, U1016, Institut Cochin; CNRS, UMR 8104; Université Paris Descartes, Sorbonne Paris Cité, Paris
| | - Anne-Laure Bulteau
- Authors' Affiliations: Inserm, U1016, Institut Cochin; CNRS, UMR 8104; Université Paris Descartes, Sorbonne Paris Cité, Paris
| | - Anne Lombès
- Authors' Affiliations: Inserm, U1016, Institut Cochin; CNRS, UMR 8104; Université Paris Descartes, Sorbonne Paris Cité, Paris
| | - Carina Prip-Buus
- Authors' Affiliations: Inserm, U1016, Institut Cochin; CNRS, UMR 8104; Université Paris Descartes, Sorbonne Paris Cité, Paris
| | - Daniel Ricquier
- Authors' Affiliations: Inserm, U1016, Institut Cochin; CNRS, UMR 8104; Université Paris Descartes, Sorbonne Paris Cité, Paris
| | - Marie-Clotilde Alves-Guerra
- Authors' Affiliations: Inserm, U1016, Institut Cochin; CNRS, UMR 8104; Université Paris Descartes, Sorbonne Paris Cité, Paris;
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38
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Shabalina IG, Vrbacký M, Pecinová A, Kalinovich AV, Drahota Z, Houštěk J, Mráček T, Cannon B, Nedergaard J. ROS production in brown adipose tissue mitochondria: the question of UCP1-dependence. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:2017-2030. [PMID: 24769119 DOI: 10.1016/j.bbabio.2014.04.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 04/08/2014] [Accepted: 04/14/2014] [Indexed: 02/05/2023]
Abstract
Whether active UCP1 can reduce ROS production in brown-fat mitochondria is presently not settled. The issue is of principal significance, as it can be seen as a proof- or disproof-of-principle concerning the ability of any protein to diminish ROS production through membrane depolarization. We therefore undertook a comprehensive investigation of the significance of UCP1 for ROS production, by comparing the ROS production in brown-fat mitochondria isolated from wildtype mice (that display membrane depolarization) or from UCP1(-/-) mice (with a high membrane potential). We tested the significance of UCP1 for glycerol-3-phosphate-supported ROS production by three methods (fluorescent dihydroethidium and the ESR probe PHH for superoxide, and fluorescent Amplex Red for hydrogen peroxide), and followed ROS production also with succinate, acyl-CoA or pyruvate as substrate. We studied the effects of the reverse electron flow inhibitor rotenone, the UCP1 activity inhibitor GDP, and the uncoupler FCCP. We also examined the effect of a physiologically induced increase in UCP1 amount. We noted GDP effects that were not UCP1-related. We conclude that only ROS production supported by exogenously added succinate was affected by the presence of active UCP1; ROS production supported by any other tested substrate (including endogenously generated succinate) was unaffected. This conclusion indicates that UCP1 is not involved in control of ROS production in brown-fat mitochondria. Extrapolation of these data to other tissues would imply that membrane depolarization may not necessarily decrease physiologically relevant ROS production. This article is a part of a Special Issue entitled: 18th European Bioenergetics Conference (Biochim. Biophys. Acta, Volume 1837, Issue 7, July 2014).
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Affiliation(s)
- Irina G Shabalina
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Marek Vrbacký
- Department of Bioenergetics, Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic
| | - Alena Pecinová
- Department of Bioenergetics, Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic
| | - Anastasia V Kalinovich
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Zdeněk Drahota
- Department of Bioenergetics, Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic
| | - Josef Houštěk
- Department of Bioenergetics, Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic
| | - Tomáš Mráček
- Department of Bioenergetics, Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic
| | - Barbara Cannon
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden.
| | - Jan Nedergaard
- Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden
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Donadelli M, Dando I, Fiorini C, Palmieri M. UCP2, a mitochondrial protein regulated at multiple levels. Cell Mol Life Sci 2014; 71:1171-90. [PMID: 23807210 PMCID: PMC11114077 DOI: 10.1007/s00018-013-1407-0] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 05/16/2013] [Accepted: 06/10/2013] [Indexed: 12/11/2022]
Abstract
An ever-increasing number of studies highlight the role of uncoupling protein 2 (UCP2) in a broad range of physiological and pathological processes. The knowledge of the molecular mechanisms of UCP2 regulation is becoming fundamental in both the comprehension of UCP2-related physiological events and the identification of novel therapeutic strategies based on UCP2 modulation. The study of UCP2 regulation is a fast-moving field. Recently, several research groups have made a great effort to thoroughly understand the various molecular mechanisms at the basis of UCP2 regulation. In this review, we describe novel findings concerning events that can occur in a concerted manner at various levels: Ucp2 gene mutation (single nucleotide polymorphisms), UCP2 mRNA and protein expression (transcriptional, translational, and protein turn-over regulation), UCP2 proton conductance (ligands and post-transcriptional modifications), and nutritional and pharmacological regulation of UCP2.
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Affiliation(s)
- Massimo Donadelli
- Section of Biochemistry, Deparment of Life and Reproduction Sciences, University of Verona, Strada Le Grazie 8, 37134, Verona, Italy,
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40
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Inhibition of high glucose-induced apoptosis by uncoupling protein 2 in human umbilical vein endothelial cells. Int J Mol Med 2014; 33:1275-81. [PMID: 24584700 DOI: 10.3892/ijmm.2014.1676] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 02/21/2014] [Indexed: 11/05/2022] Open
Abstract
Studies have shown that an overproduction of mitochondrial reactive oxygen species (ROS) is an initiating cause in the pathogenesis of diabetic complications. However, uncoupling protein 2 (UCP2) can protect retinal vascular endothelial cells from damage by inhibiting the overproduction of mitochondrial ROS, although the protective mechanism involved is not completely clear. This study aimed to assess the effect and mechanism of UCP2 on the apoptosis of human umbilical vein endothelial cells (HUVECs). HUVECs were cultured in normal glucose (NG, 5.5 mmol/l) or high glucose (HG, 30 mmol/l) medium in the presence or absence of UCP2(+/+) lentiviral transfection. Lentivirus-mediated UCP2 overexpression inhibited the apoptosis of HUVECs induced by HG. Treatment with HG resulted in the upregulation of caspase-3 and cytochrome c and the downregulation of Bcl-2 in vitro. Furthermore, compared with the NG group, the rate of apoptosis was significantly increased in the HG group. On day two post-infection, NG cells showed significantly greater HUVEC cell proliferation than HG cells. Notably, UCP2 overexpression inhibited these processes. Taken together, these results suggest that UCP2 promotes cell proliferation and inhibits HG-induced apoptosis in HUVECs via the Bcl-2 up‑ and downregulation of caspase-3 and cytochrome c in vitro. This may provide experimental evidence for the application of UCP2 as a new protective factor for diabetic complications, such as diabetic retinopathy.
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41
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JEŽEK P, OLEJÁR T, SMOLKOVÁ K, JEŽEK J, DLASKOVÁ A, PLECITÁ-HLAVATÁ L, ZELENKA J, ŠPAČEK T, ENGSTOVÁ H, PAJUELO REGUERA D, JABŮREK M. Antioxidant and Regulatory Role of Mitochondrial Uncoupling Protein UCP2 in Pancreatic β-cells. Physiol Res 2014; 63:S73-91. [DOI: 10.33549/physiolres.932633] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Research on brown adipose tissue and its hallmark protein, mitochondrial uncoupling protein UCP1, has been conducted for half a century and has been traditionally studied in the Institute of Physiology (AS CR, Prague), likewise UCP2 residing in multiple tissues for the last two decades. Our group has significantly contributed to the elucidation of UCP uncoupling mechanism, fully dependent on free fatty acids (FFAs) within the inner mitochondrial membrane. Now we review UCP2 physiological roles emphasizing its roles in pancreatic β-cells, such as antioxidant role, possible tuning of redox homeostasis (consequently UCP2 participation in redox regulations), and fine regulation of glucose-stimulated insulin secretion (GSIS). For example, NADPH has been firmly established as being a modulator of GSIS and since UCP2 may influence redox homeostasis, it likely affects NADPH levels. We also point out the role of phospholipase iPLA2 isoform in providing FFAs for the UCP2 antioxidant function. Such initiation of mild uncoupling hypothetically precedes lipotoxicity in pancreatic β-cells until it reaches the pathological threshold, after which the antioxidant role of UCP2 can be no more cell-protective, for example due to oxidative stress-accumulated mutations in mtDNA. These mechanisms, together with impaired autocrine insulin function belong to important causes of Type 2 diabetes etiology.
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Affiliation(s)
- P. JEŽEK
- Department of Membrane Transport Biophysics, Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Quintero M, Gonzalez-Martin MDC, Vega-Agapito V, Gonzalez C, Obeso A, Farré R, Agapito T, Yubero S. The effects of intermittent hypoxia on redox status, NF-κB activation, and plasma lipid levels are dependent on the lowest oxygen saturation. Free Radic Biol Med 2013; 65:1143-1154. [PMID: 24002010 DOI: 10.1016/j.freeradbiomed.2013.08.180] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 08/01/2013] [Accepted: 08/23/2013] [Indexed: 12/11/2022]
Abstract
Obstructive sleep apnea syndrome (OSAS) is described as repetitive obstructions of the upper airways during sleep, causing concomitant episodes of systemic hypoxia and associated cardiovascular and metabolic pathologies. The mechanisms generating these pathologies are controversial. Because recurrent hypoxia is the element of inadequate respiration that leads to the pathology, experimental models of OSAS consist in the exposure of the animals to intermittent hypoxia (IH) by cycling O2 percentages in their habitats. A proposed mechanism linking the IH of OSAS to pathologies is the increased production of reactive oxygen species (ROS). However, it has been argued that many patients seem to lack oxidative stress and that, to augment ROS in IH animals, intense hypoxia, seldom encountered in patients, has to be applied. To solve the controversy, we have exposed rats to two intensities of IH (cycles of 10 or 5% O2, 40s, and then 21% O2, 80s; 8h/day, 15 days). We then measured reduced and oxidized glutathione and lipid peroxide levels, aconitase and fumarase activities, and ROS-disposal enzyme activity in liver, brain, and lung. Liver levels of nuclear NF-κB-p65 and plasma C-reactive protein (CRP), as well as lipid levels, were also assessed. Lowest hemoglobin saturations were 91.7 ± 0.8 and 73.5 ± 1.4%. IH caused tissue-specific oxidative stress related to hypoxic intensity. Nuclear NF-κB-p65 and lipid content in the liver and CRP in the plasma all increased with IH intensity, as did both plasma triglycerides and cholesterol. We conclude that IH, even of moderate intensity, causes oxidative stress probably related to the pathologies encountered in OSAS patients.
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Affiliation(s)
- Miguel Quintero
- Institute of Molecular Biology and Genetics, CSIC, Department of Biochemistry and Molecular Biology and Physiology, School of Medicine, University of Valladolid, 47005 Valladolid, Spain
| | - María Del Carmen Gonzalez-Martin
- Institute of Molecular Biology and Genetics, CSIC, Department of Biochemistry and Molecular Biology and Physiology, School of Medicine, University of Valladolid, 47005 Valladolid, Spain
| | - Victoria Vega-Agapito
- Institute of Molecular Biology and Genetics, CSIC, Department of Biochemistry and Molecular Biology and Physiology, School of Medicine, University of Valladolid, 47005 Valladolid, Spain
| | - Constancio Gonzalez
- Institute of Molecular Biology and Genetics, CSIC, Department of Biochemistry and Molecular Biology and Physiology, School of Medicine, University of Valladolid, 47005 Valladolid, Spain; CIBER Enfermedades Respiratorias, Institute of Salud Carlos III, 28029 Madrid, Spain
| | - Ana Obeso
- Institute of Molecular Biology and Genetics, CSIC, Department of Biochemistry and Molecular Biology and Physiology, School of Medicine, University of Valladolid, 47005 Valladolid, Spain; CIBER Enfermedades Respiratorias, Institute of Salud Carlos III, 28029 Madrid, Spain
| | - Ramon Farré
- CIBER Enfermedades Respiratorias, Institute of Salud Carlos III, 28029 Madrid, Spain; Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona-IDIBAPS, Barcelona, Spain
| | - Teresa Agapito
- Institute of Molecular Biology and Genetics, CSIC, Department of Biochemistry and Molecular Biology and Physiology, School of Medicine, University of Valladolid, 47005 Valladolid, Spain; CIBER Enfermedades Respiratorias, Institute of Salud Carlos III, 28029 Madrid, Spain
| | - Sara Yubero
- Institute of Molecular Biology and Genetics, CSIC, Department of Biochemistry and Molecular Biology and Physiology, School of Medicine, University of Valladolid, 47005 Valladolid, Spain; CIBER Enfermedades Respiratorias, Institute of Salud Carlos III, 28029 Madrid, Spain.
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43
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Malingriaux EA, Rupprecht A, Gille L, Jovanovic O, Jezek P, Jaburek M, Pohl EE. Fatty acids are key in 4-hydroxy-2-nonenal-mediated activation of uncoupling proteins 1 and 2. PLoS One 2013; 8:e77786. [PMID: 24204965 PMCID: PMC3810126 DOI: 10.1371/journal.pone.0077786] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 09/12/2013] [Indexed: 11/19/2022] Open
Abstract
The production of reactive oxygen species (ROS) in mitochondria is very sensitive to the proton motive force and may be decreased by mild uncoupling, mediated e.g. by mitochondrial uncoupling proteins (UCPs). UCPs were conversely hypothesized to be activated by ROS. Conclusions from experiments studying the reactive product of lipid peroxidation 4-hydroxy-2-nonenal (HNE) in isolated mitochondria and UCP knock-out mice are highly controversial. Here we investigated the molecular mechanism of HNE action by evaluating the separate contributions of lipid and protein phases of the membrane and by comparing UCP1 and UCP2, which were reconstituted in planar lipid bilayers. We demonstrated that aldehyde does not directly activate either UCP1 or UCP2. However, HNE strongly potentiated the membrane conductance increase (Gm) mediated by different long-chain fatty acids in UCP-containing and in UCP-free membranes and this suggest the involvement of both lipid-mediated and protein-mediated mechanisms with FA playing the central role. Gm increase was concentration-dependent and exhibited a typical saturation kinetic with the binding constant 0.3 mM. By using Electron Paramagnetic Resonance, membrane fluidity change could be excluded as a cause for the HNE-mediated increase in the presence of FA. The impact of the HNE binding to definite positively charged UCP amino acid residues is discussed as a possible protein-mediated mechanism of the UCP activation.
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Affiliation(s)
- Elena A. Malingriaux
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Anne Rupprecht
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Lars Gille
- Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Vienna, Austria
| | - Olga Jovanovic
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Petr Jezek
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Martin Jaburek
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Elena E. Pohl
- Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
- * E-mail:
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Anedda A, López-Bernardo E, Acosta-Iborra B, Saadeh Suleiman M, Landázuri MO, Cadenas S. The transcription factor Nrf2 promotes survival by enhancing the expression of uncoupling protein 3 under conditions of oxidative stress. Free Radic Biol Med 2013; 61:395-407. [PMID: 23597505 DOI: 10.1016/j.freeradbiomed.2013.04.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 04/01/2013] [Accepted: 04/05/2013] [Indexed: 10/27/2022]
Abstract
Uncoupling protein 3 (UCP3) is a member of the mitochondrial inner membrane carrier superfamily that modulates energy efficiency by catalyzing proton conductance and thus decreasing the production of superoxide anion. However, its role during oxidative stress and the underlying regulatory and molecular mechanisms remain poorly understood. We sought to investigate how UCP3 expression is regulated by oxidative stress and to evaluate the putative antioxidant role of this protein. H2O2 treatment increased UCP3 expression and the nuclear accumulation of the transcription factor Nrf2 in C2C12 and HL-1 cells. Nrf2 siRNA prevented H2O2-induced UCP3 expression, increasing oxidative stress and cell death. ChIP assays identified an antioxidant-response element (ARE) within the UCP3 promoter that bound Nrf2 after exposure to H2O2. Luciferase reporter experiments confirmed increased ARE activity in H2O2-treated HL-1 cells. Importantly, H2O2 increased the UCP3-mediated proton leak, suggesting a role for this protein in attenuating ROS-induced damage. Nrf2 nuclear accumulation and increased UCP3 protein were also detected in intact mouse heart subjected to a condition known to increase ROS generation. This is the first study to demonstrate that H2O2 augments UCP3 expression and it provides the first evidence of Nrf2 binding to the UCP3 promoter in response to oxidative challenge. These findings suggest that UCP3 functions as a member of the cellular antioxidant defense system that protects against oxidative stress in vivo. In conclusion, we have identified a novel regulatory process induced by an oxidative insult whereby the expression of the mitochondrial protein UCP3 is driven by the Nrf2 transcription factor, which decreases ROS production and prevents cell death.
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Affiliation(s)
- Andrea Anedda
- Servicio de Inmunología, Hospital Universitario de La Princesa, Instituto de Investigación Sanitaria Princesa (IP), 28006 Madrid, Spain
| | - Elia López-Bernardo
- Servicio de Inmunología, Hospital Universitario de La Princesa, Instituto de Investigación Sanitaria Princesa (IP), 28006 Madrid, Spain
| | - Bárbara Acosta-Iborra
- Servicio de Inmunología, Hospital Universitario de La Princesa, Instituto de Investigación Sanitaria Princesa (IP), 28006 Madrid, Spain; Unidad de Investigación, Hospital Universitario Santa Cristina, Instituto de Investigación Sanitaria Princesa (IP), 28009 Madrid, Spain
| | | | - Manuel O Landázuri
- Servicio de Inmunología, Hospital Universitario de La Princesa, Instituto de Investigación Sanitaria Princesa (IP), 28006 Madrid, Spain; Unidad de Investigación, Hospital Universitario Santa Cristina, Instituto de Investigación Sanitaria Princesa (IP), 28009 Madrid, Spain
| | - Susana Cadenas
- Servicio de Inmunología, Hospital Universitario de La Princesa, Instituto de Investigación Sanitaria Princesa (IP), 28006 Madrid, Spain; Departamento de Biología Molecular, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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45
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Graw JA, von Haefen C, Poyraz D, Möbius N, Sifringer M, Spies CD. Chronic alcohol consumption increases the expression of uncoupling protein-2 and -4 in the brain. Alcohol Clin Exp Res 2013; 37:1650-6. [PMID: 23800309 DOI: 10.1111/acer.12144] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 03/07/2013] [Indexed: 01/07/2023]
Abstract
BACKGROUND Chronic alcohol consumption leads to oxidative stress in a variety of cells, especially in brain cells because they have a reduced oxidative metabolism of alcohol. Uncoupling proteins (UCPs) are anion channels of the inner mitochondrial membrane, which can decouple internal respiration. "Mild uncoupling" of the mitochondrial respiratory chain leads to a reduced production of free radicals (reactive oxygen species) and a reduction in oxidative cell stress. The extent to which chronic alcohol consumption regulates UCP-2 and -4 in the brain is still unknown. METHODS We examined the effects of a 12-week 5% alcohol diet in the brain of male Wistar rats (n = 34). Cerebral gene and protein expression of UCP-2, -4, as well as Bcl-2, and the release of cytochrome c out of the mitochondria were detected by real-time polymerase chain reaction and Western blot analysis. The percentage of degenerated cells was determined by Fluoro-Jade B staining of brain slices. RESULTS Brains of rats with a chronic alcohol diet showed an increased gene and protein expression of UCP-2 and -4. The expression of the antiapoptotic protein Bcl-2 in the brain of the alcohol-treated animals was decreased significantly, whereas cytochrome c release from mitochondria was increased. In addition increased neurodegeneration could be demonstrated in the alcohol-treated animals. CONCLUSIONS Chronic alcohol consumption leads to a cerebral induction of UCP-2 and -4 with a simultaneous decrease in the antiapoptotic protein Bcl-2, cytochrome c release from mitochondria and increased neurodegeneration. This study reveals a compensatory effect of UCP-2 and -4 in the brain during chronic alcohol consumption.
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Affiliation(s)
- Jan A Graw
- Department of Anesthesiology and Intensive Care Medicine, Campus Charité Mitte and Campus Virchow-Klinikum, Charité-Universitätsmedizin Berlin, Berlin, Germany
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46
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Allister EM, Robson-Doucette CA, Prentice KJ, Hardy AB, Sultan S, Gaisano HY, Kong D, Gilon P, Herrera PL, Lowell BB, Wheeler MB. UCP2 regulates the glucagon response to fasting and starvation. Diabetes 2013; 62:1623-33. [PMID: 23434936 PMCID: PMC3636632 DOI: 10.2337/db12-0981] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Glucagon is important for maintaining euglycemia during fasting/starvation, and abnormal glucagon secretion is associated with type 1 and type 2 diabetes; however, the mechanisms of hypoglycemia-induced glucagon secretion are poorly understood. We previously demonstrated that global deletion of mitochondrial uncoupling protein 2 (UCP2(-/-)) in mice impaired glucagon secretion from isolated islets. Therefore, UCP2 may contribute to the regulation of hypoglycemia-induced glucagon secretion, which is supported by our current finding that UCP2 expression is increased in nutrient-deprived murine and human islets. Further to this, we created α-cell-specific UCP2 knockout (UCP2AKO) mice, which we used to demonstrate that blood glucose recovery in response to hypoglycemia is impaired owing to attenuated glucagon secretion. UCP2-deleted α-cells have higher levels of intracellular reactive oxygen species (ROS) due to enhanced mitochondrial coupling, which translated into defective stimulus/secretion coupling. The effects of UCP2 deletion were mimicked by the UCP2 inhibitor genipin on both murine and human islets and also by application of exogenous ROS, confirming that changes in oxidative status and electrical activity directly reduce glucagon secretion. Therefore, α-cell UCP2 deletion perturbs the fasting/hypoglycemic glucagon response and shows that UCP2 is necessary for normal α-cell glucose sensing and the maintenance of euglycemia.
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Affiliation(s)
- Emma M. Allister
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | | | - Kacey J. Prentice
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Alexandre B. Hardy
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Sobia Sultan
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Herbert Y. Gaisano
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Dong Kong
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Patrick Gilon
- Pôle d’endocrinologie, diabète et nutrition, Institut de recherche expérimentale et clinique, Université catholique de Louvain, Brussels, Belgium
| | - Pedro L. Herrera
- Department of Genetic Medicine and Development, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Bradford B. Lowell
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts
| | - Michael B. Wheeler
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Corresponding author: Michael B. Wheeler,
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Rodríguez-Jimnez FJ, Alastrue-Agudo A, Erceg S, Stojkovic M, Moreno-Manzano V. FM19G11 favors spinal cord injury regeneration and stem cell self-renewal by mitochondrial uncoupling and glucose metabolism induction. Stem Cells 2013; 30:2221-33. [PMID: 22865656 DOI: 10.1002/stem.1189] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Spinal cord injury is a major cause of paralysis with no currently effective therapies. Induction of self-renewal and proliferation of endogenous regenerative machinery with noninvasive and nontoxic therapies could constitute a real hope and an alternative to cell transplantation for spinal cord injury patients. We previously showed that FM19G11 promotes differentiation of adult spinal cord-derived ependymal stem cells under hypoxia. Interestingly, FM19G11 induces self-renewal of these ependymal stem cells grown under normoxia. The analysis of the mechanism of action revealed an early increment of mitochondrial uncoupling protein 1 and 2 with an early drop of ATP, followed by a subsequent compensatory recovery with activated mitochondrial metabolism and the induction of glucose uptake by upregulation of the glucose transporter GLUT-4. Here we show that phosphorylation of AKT and AMP-activated kinase (AMPK) is involved in FM19G11-dependent activation of GLUT-4, glucose influx, and consequently in stem cell self-renewal. Small interfering RNA of uncoupling protein 1/2, GLUT-4 and pharmacological inhibitors of AKT, mTOR and AMPK signaling blocked the FM19G11-dependent induction of the self-renewal-related markers Sox2, Oct4, and Notch1. Importantly, FM19G11-treated animals showed accelerated locomotor recovery. In vivo intrathecal sustained administration of FM19G11 in rats after spinal cord injury showed more neurofilament TUJ1-positive fibers crossing the injured area surrounded by an increase of neural precursor Vimentin-positive cells. Overall, FM19G11 exerts an important influence on the self-renewal of ependymal stem progenitor cells with a plausible neuroprotective role, providing functional benefits for spinal cord injury treatment.
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Santo-Domingo J, Demaurex N. Perspectives on: SGP symposium on mitochondrial physiology and medicine: the renaissance of mitochondrial pH. ACTA ACUST UNITED AC 2013; 139:415-23. [PMID: 22641636 PMCID: PMC3362525 DOI: 10.1085/jgp.201110767] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Jaime Santo-Domingo
- Department of Cell Physiology and Metabolism, University of Geneva, CH-1211 Geneva, Switzerland
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Vera-Ramirez L, Pérez-Lopez P, Varela-Lopez A, Ramirez-Tortosa M, Battino M, Quiles JL. Curcumin and liver disease. Biofactors 2013; 39:88-100. [PMID: 23303639 DOI: 10.1002/biof.1057] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 09/13/2012] [Indexed: 12/12/2022]
Abstract
Liver diseases pose a major medical problem worldwide and a wide variety of herbs have been studied for the management of liver-related diseases. In this respect, curcumin has long been used in traditional medicine, and in recent years it has been the object of increasing research interest. In combating liver diseases, it seems clear that curcumin exerts a hypolipidic effect, which prevents the fatty acid accumulation in the hepatocytes that may result from metabolic imbalances, and which may cause nonalcoholic steatohepatitis. Another crucial protective activity of curcumin, not only in the context of chronic liver diseases but also regarding carcinogenesis and other age-related processes, is its potent antioxidant activity, which affects multiple processes and signaling pathways. The effects of curcumin on NF-κβ are crucial to our understanding of the potent hepatoprotective role of this herb-derived micronutrient. Because curcumin is a micronutrient that is closely related to cellular redox balance, its properties and activity give rise to a series of molecular reactions that in every case and biological situation affect the mitochondria.
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Affiliation(s)
- Laura Vera-Ramirez
- GENyO Center Pfizer-University of Granada & Andalusian Government Centre for Genomics & Oncology, Granada, Spain
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50
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Porter RK. Studies on the function and regulation of mitochondrial uncoupling proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 748:171-84. [PMID: 22729858 DOI: 10.1007/978-1-4614-3573-0_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Mitochondrial uncoupling proteins are members of the SLC25 family of solute carriers. Models of mitochondrial transporter function predict that uncoupling proteins are solute carriers. Evidence in the literature suggests that uncoupling proteins can transport protons, fatty acid anions, chloride anions, and recently the dicarboxylate succinate. Studies have also demonstrated that UCPs can be covalently modified and in some instances this covalent modification is needed to affect uncoupling function. The current evidence from functional analyses of mammalian uncoupling proteins is summarized in this chapter.
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Affiliation(s)
- Richard K Porter
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland.
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